Karst topography is a special landscape shaped by the dissolution of one or more layers of soluble bedrock, usually carbonate rock such as limestone or dolomite. Due to subterranean drainage, overland flow, extraction of water by plants and evapotranspiration, there may be very limited surface water. The hydraulic architecture that plants use to adapt to karst topography is very interesting, bu...

Predicting the hydrologic consequences of biomass cropping systems requires an understanding of how different crops and management practices affect soil hydraulic properties across space and time. To inform such predictions, I investigated the impacts of five biomass cropping systems on the hydraulic properties of soils across a landscape gradient in wet, dry, and average rainfall years. I used...

PREMISE OF THE STUDY The Pacific Northwest of North America experiences relatively mild winters and dry summers. For the tall coniferous trees that grow in this region, we predicted that loss in the hydraulic conductivity of uppermost branches would be avoided because of difficulty reversing accumulated emboli in xylem that is always under negative pressure. METHODS To test this hypothesis, w...

Many flows observed in subsurface rock formations are unsaturated flows through a medium containing fractures. In cases where the fracture voids are small and nonconnective, one finds that little flow occurs within those voids. Under these conditions, the fractures act as barriers which impede background flow in the underlying matrix. From a computational point of view, discrete modeling of the...

The microstructure of a porous medium and the physical characteristics of the solid and fluid phases determine the macroscopic transport properties of the medium. The purpose of this paper is to test numerical calculations of the geometrical and transport properties (electrical conductivity, permeability, specific surface area, and surface conductivity) of porous, permeable rocks, given their 3...

The unsaturated soil hydraulic properties are often described using Mualem–van Genuchten (MVG) type analytical functions. Recent studies suggest several shortcomings of these functions near saturation, notably the lack of second-order continuity of the soil water retention function at saturation and the inability of the hydraulic conductivity function to account for macroporosity. We present a ...

abstract pedotransfer functions (ptfs) are useful means of prediction many properties of the soil, and especially the hydraulic characteristics of this porous media. the main advantages of this functions, as compare to conventional methods used to directly estimate soil hydraulic properties, is that they are not time-cost consuming. different approaches such as classic linear and non linear reg...

The aim of this paper was to verify the common methods of hydraulic conductivity estimation for soil assessment in respect to wastewater disposal. The studies were conducted on three types of sandy soils. Hydraulic conductivity was determined using a scale effect-free laboratory method, empirical equations and compared with measurements estimated from a laboratory infiltration column with ident...

To gain insights into the natural variation of root hydraulics and its molecular components, genotypic differences related to root water transport and plasma membrane intrinsic protein (PIP) aquaporin expression were investigated in 13 natural accessions of Arabidopsis (Arabidopsis thaliana). The hydraulic conductivity of excised root systems (Lpr) showed a 2-fold variation among accessions. Th...

leaf hydraulic conductance, components of tissue water potential, hydraulic architecture parameters and xylem embolism were examined in greenhouse-grown two-year-old Aleppo pine (Pinus halepensis Mill.) seedlings from six origins representing the geographic range of the species in Italy. Cortical resin composition of the seedlings was also determined. Measurements were made on well-watered seed...